Improvement in making rubber stereotypes



HENRY u. PERKY. Making Rubber Stereotypes.

' Patented Oct. 1

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PATENT OFFICE.

HENRY D. PERKY, OF WASHINGTON, DISTRICT OF COLUMBIA.

IMPROVEMENT IN MAKING RUBBER STEREQTVPES.

Specification forming part of Letters Patent No. 120,096, dated October 17, 1871.

To all whom it may concern:

Be it known that I, HENRY D. PERKY, of the city of Washington, in the county of Washington, District of Columbia, have invented a certain Improved Method of Producing Flexible Forms for Printing, of I which the following is a specification My apparatus consists of a press adapted for the application to it of dry heat, and constructed with an extended bed or table, on which the mold may be set to dry. The said mold consists of a bed of plaster, Contained within an inclosing-rim or chase of brass and the matrix may be formed in the face of the said plaster by means of common type. The entire press is constructed of brass to adapt it for the more free conduction of heat.

In the drawing, Figure l is a longitudinal section of the apparatus. Fig. 2 is a transverse section thereof at as m, Fig. 1, having the mold I and rubber sheet K in place. Fig. 3 is aperspective view of the mold detached.

A represents the frame; B, the bed; 0, the platen; D, the screw; and E, the hand-wheel of a press. These parts may be of any common form. This press is supported on feet F, so as to admit beneath the bed a lamp G for the purpose of heating it. From the bed extends on one side a shelf or table, H, on which the mold is placed to dry, while the press is being heated. I represents the body of the mold, formed of plaster of Paris or other suitable material; and J a metallic rim or chase,'within which it is contained. K is the sheet of rubber composition, upon which the impression is taken in relief.

In applying the apparatus I form the mold with plaster in the way that stereotype-molds are made. The mold thus produced is placed on the table H to dry, the platen O is screwed down in contact with the bed B, and the lamp G placed beneath in order to heat the press. This being accomplished, a piece of the necessary size cut from the sheet of soft vulcanized-rubber composition is laid upon the face of the mold, and the latter placed within the press, a piece of paper being placed over the rubber sheet. The platen I) is nowscrewed down, forcing the rubber into all the cavities of the matrix, so as to produce a sharp and accurate impression in relief. After remaining thus within the heated press for a limited period, say ten minutes, the rubber type or stamp will be completely and permanently formed, and may after cooling be taken out of the mold and applied to the face of a block or stock of suitable form for use.

The entire press and the table H and chase J are constructed of brass to adapt them to take the heat more readily and uniformly.

I claim as my invention- The process herein described for producing flexible printing-forms from vulcanized rubber composition by the combined agency of pressure and dry heat, applied as above set ibrth.

Witnesses: HENRY D. PERKY.

OOTAVIUS KNIGHT,

WM. H. BRERETON, Jr. (164) 

